Rapid exchange dilation catheter for non-vascular applications

ABSTRACT

A flexible catheter for insertion into a body lumen, comprises a guide wire lumen extending from a distal port at a distal end of the catheter to a proximal port separated from a proximal end of the catheter and a stiffening member extending from the proximal port to a proximal end of the catheter.

FIELD OF THE INVENTION

The present invention is applicable to the field of catheters, and inparticular to the field of balloon catheters used for dilation of bodycavities.

BACKGROUND OF THE INVENTION

Endoscopic procedures for treating abnormal pathologies within variousbody cavities, such as, for example, the alimentary canal, the biliarytree and the pulmonary system are increasing in number. In theseprocedures, an endoscope may provide access to the general area of adesired cavity or duct using direct visualization. However, smallerducts may require navigation using a only a catheter in conjunction withfluoroscopy and guide wires.

In many cases, treatment of the areas within such small diameter ductsrequires use of more than one catheter, necessitating a catheterexchange during the procedure. These catheters may, for example, bespecialized for the delivery of contrast media for fluoroscopicvisualization of the anatomical details of the duct, to delivertherapeutic agents, or to perform a dilation of the duct. In the lattercase, the catheter may include an expandable portion that mechanicallydilates the duct when expanded. A catheter exchange typically involvesremoving the first catheter from the endoscope, over the guide wire, andadvancing a second catheter over the guide wire to the desired treatmentsite. Once the guide wire is in place relative to the targeted area, itis highly desirable to maintain the position of the guide wire duringsubsequent catheter procedures, including during catheter exchanges, tofacilitate positioning subsequently utilized catheters or other devicesat the target area. If the guide wire's positioning at the target areais lost during such a procedure, re-directing the guide wire through thebody ducts to the target site may be difficult and time consuming.

To maintain the position of the guide wire, a physician typically graspsthe proximal end of the guide wire and/or catheter with one hand whileperforming the corresponding exchange with the other. For certainprocedures, the length of the standard guide wire may be insufficient toallow a physician to maintain his grasp of the catheter as the fulllength of the catheter is removed thereover. To alleviate thisdifficulty, additional devices such as guide wire extenders may be used.However, utilizing such additional devices adds to the complexity of andtime required for the exchange. In addition, the extended length of theguide wire (up to two meters or more) may require a second operator toassist in handling the apparatus during the procedure.

SUMMARY OF THE INVENTION

The present invention is directed to a flexible catheter for insertioninto a body lumen, comprising a guide wire lumen extending from a distalport at a distal end of the catheter to a proximal port separated from aproximal end of the catheter and a stiffening member extending from theproximal port to a proximal end of the catheter.

The present invention is further directed to a method of treating tissueat a target location within a body lumen, comprising the steps ofinserting a guide wire through the body lumen to the target location,inserting a proximal end of the guide wire into a distal port of a guidewire lumen of a catheter and sliding the catheter therealong until theguide wire exits a proximal port thereof, the proximal port of the guidewire being spaced from a proximal end of the catheter and, wherein thecatheter includes a stiffening member extending from the proximal endthereof to a location adjacent to the proximal port of the guide wirelumen in combination with the steps of sliding the catheter along theguide wire to the target location and treating tissue at the targetlocation using the catheter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing an embodiment of the rapid exchangeballoon catheter according to the present invention;

FIG. 2 is a cross sectional view on line II—II of the rapid exchangecatheter shown in FIG. 1; and

FIG. 3 is a cross sectional view on line III—III of the rapid exchangecatheter shown in FIG. 1.

DETAILED DESCRIPTION

The present invention may be further understood with reference to thefollowing description and the appended drawings, wherein like elementsare referred to with the same reference numerals. According toembodiments of the present invention, a rapid exchange catheter isutilized to dilate any of various body cavities, and in particularnon-vascular body cavities such as gastrointestinal passages, biliary,hepatic and pancreatic ducts, pulmonary passages and the like. However,those skilled in the art will understand that the catheter according tothe present invention may be employed in any body lumen which aphysician wishes to dilate. As described below, the catheter may includelumens adapted for any or all of the various functions described hereinas well as lumens for any other known purpose.

Embodiments according to the present invention facilitate the insertionof the catheter over a guide wire, and simplify exchanges of catheterswithout disturbing a positioning of the guide wire at a target location.As described in more detail below, embodiments of the present inventionallow shorter guide wires to be utilized while maintaining the abilityof a physician to maintain a secure grip on the wire during exchangeprocedures.

A typical procedure using a catheter in a small, non-vascular targetpassage or duct, may begin with the insertion of an endoscope or abronchoscope to visualize the larger body cavities leading to the targetpassage. For target areas located within small diameter ducts, theendoscope's large size may make it impossible to directly access thetarget area with the endoscope. Therefore, these ducts must be accessedby extending a catheter and guide wire combination distally from theendoscope through the small diameter ducts to the target area. The guidewire is often inserted first under, for example, fluoroscopic guidanceor another method known in the art. The guide wire may be extended fromwithin a lumen of the endoscope, or may be inserted separately,alongside the endoscope. The guide wire may thus be viewed both throughthe endoscope, and using fluoroscopy. Once the distal end of the guidewire has reached the target area, it is important to maintain it inplace. If the position is lost, the guide wire must be guided again intoposition, significantly adding to the time required to complete theprocedure.

Once the guide wire is in place, a catheter may be extended, for examplefrom within a lumen of the endoscope, along the guide wire to the targetlocation. For example, the catheter may include a guide wire lumenthrough which the guide wire passes. The catheter may, for example, be“threaded” onto the guide wire, so that the guide wire enters the guidewire lumen near a distal tip of the catheter, follows it along a portionof the length thereof, and exits at a more proximal location along thecatheter. The guide wire is free to slide longitudinally within theguide wire lumen of the catheter, but is constrained radially by thewalls of the guide wire lumen. In addition to guiding the catheter, theguide wire also provides a certain amount of stiffness to the catheter,so that it will not buckle as readily as it might without a guide wirereceived therein.

FIG. 1 shows an exemplary embodiment of a rapid exchange dilationcatheter 10 according to the present invention. As described above, aswould be understood by those of skill in the art, the dilation catheter10 may be extended into the body from an endoscope or from abronchoscope (not shown in the drawings), or may be inserted directlyinto a body cavity, depending on the application. The dilation catheter10 extends from a distal end 22 and a proximal end 24. The distal end 22is adapted to be inserted inside a body lumen via, for example, anatural body orifice or a surgical opening while the proximal end 24typically remains outside of the body cavity throughout the procedure,and may, for example, include a handle, the various actuators orcontrols and connections necessary to operate the catheter 10. As wouldbe understood by those of skill in the art, the catheter 10 ispreferably a flexible, multi-lumen catheter, so that it is able tofollow the guide wire through narrow body cavities and ducts. Those ofskill in the art will appreciate that different structural constructionsof the catheter may be employed, while remaining within the scope of thepresent invention.

As shown in FIGS. 1–3, the catheter 10 may include an expandableelement, for dilating the lumen at the area to be treated. For example,the expandable element may include a balloon portion 16 formed near thedistal end 22, so that, when inflated, the balloon portion 16 expands adiameter of the lumen adjacent to the target location in the ductpinpointed by the distal end 26 of guide wire 14. In this manner, theballoon portion 16 may be accurately moved to the target location bymoving the catheter 10 along the guide wire 14. As would be understoodby those of skill in the art, the balloon portion 16 may be coupled to asource of inflation fluid via an inflation lumen 34 which may beconnected to a fluid supply tube 30 at one end, and to the balloonportion 16 at the other end. A valve or other control device 32 may beused to selectively introduce or remove the inflation fluid, and causethe balloon portion 16 to expand or collapse. As would be understood bythose of skill in the art, the inflation fluid may comprise air, salineor other suitable fluid.

As described above, a guide wire 14 may be used according to theinvention to precisely locate the distal end 22 of catheter 10 at thetarget area. As described above, the guide wire 14 is inserted into abody cavity or duct to be treated, and the distal end 26 thereof ismaneuvered to a position adjacent to the target area. The proximal endof the guide wire 14 is then inserted into the guide wire lumen 42 ofthe catheter 10 and the catheter 10 is pushed along the guide wire 14until the distal end 22 of the catheter 10 is also adjacent to thetarget area. According to the exemplary embodiment shown, the guide wirelumen 42 extends from a distal port 18 to a proximal port 20, and passesbelow balloon portion 16, as shown in FIG. 2. The guide wire 14 isinserted into the guide wire lumen 42 via a distal port 18 and is slidtherethrough under the balloon portion 16 and out of a proximal port 20.The distal port 18 may, for example, be formed at the distal end 22, sothat the guide wire 14 exits therefrom substantially along an axis ofthe catheter 10. The proximal port 20 may, for example, be formed on aside surface of the catheter 10 spaced from a proximal end thereof sothat the guide wire 14 exits at an angle therefrom and does not passthrough a proximal part of catheter 10.

As described above, conventional over the wire catheters often require aguide wire that is more than twice the length of the catheter, as theguide wire is threaded through the entire length of the catheter. Thelength of the guide wire makes it difficult to handle the apparatus,especially if the catheter is to be replaced while maintaining the guidewire in place. According to embodiments of the present invention, theguide wire 14 may be much shorter, since it only has to extend throughthe part of catheter 10 between the distal port 18 and the proximal port20 and does not extend through that portion of the catheter 10 which isproximal of the proximal port 20. The distance between the distal port18 and the proximal port 20 is preferably significantly shorter than thetotal length of catheter 10, so that the guide wire 14 does not need tobe longer than the catheter 10 to function properly. For example, in acatheter 10 having a length of 100 cm, the proximal port 20 of the guidewire lumen 42 may be located approximately 10 cm from a proximal end ofthe balloon portion 16. Those skilled in the art will understand thatthe distance from the proximal end of the balloon from the distal port18 will vary depending on the length of the balloon employed as theballoon portion 16. The balloon will generally be between 2 cm and 10 cmin length. The length of the guide wire lumen 42, between ports 18 and20, is kept to a minimum length which allows guidance of the distal end22 and of the balloon portion 16 into the target area. In a preferredembodiment, the catheter 10 is threaded over the guide wire 14 at leastwithin the portion containing the dilation mechanism, e.g., the balloonportion 16, which must be accurately placed with respect to the targetarea. In one exemplary embodiment, the guide wire lumen may preferablyhave a length of approximately 10-15 cm.

Catheters 10 according to the invention are especially beneficial insituations where a first catheter 10 must be removed from the guide wire14 so that a second catheter, which may be of any construction, may bereplaced thereon and guided to the target area. As described above, asonly a small portion of the guide wire 14 is contained within the guidewire lumen 42, the operator may maintain hands-on control of the guidewire 14 at all times during removal of the first catheter 10 from thebody. That is, since the majority of the length of the guide wire 14 isoutside the catheter 10 and accessible, the operator may grasp the guidewire 14 near the point where it enters the body cavity to manuallyprevent it from moving out of place as the catheter 10 is retracted.When the proximal port 20 exits the body, the operator may grasp a moreproximal portion of the guide wire 14 until the distal port 18 exits thebody. At this point, the operator may grasp the portion of the guidewire 14 extending from the distal port 18 into the body while completelyremoving the catheter 10 from the guide wire 14. Thereafter, theproximal end of the guide wire 14 may be inserted into the secondcatheter in the standard manner and the second catheter may be advancedalong the guide wire 14 to the target area. In this manner, the operatormay maintain a grasp on the guide wire 14 at all times to maintain itsposition at the target area.

After the first catheter 10 has been removed, a second catheter may thenbe advanced to the target area by inserting the guide wire 14 into aguide wire lumen thereof and sliding the second catheter along the guidewire 14 to the target area. If the second catheter is also formed as acatheter 10 in accord with the present invention, the guide wire 14 willbe inserted into the distal opening 18 and drawn out of the proximalport 20 and inserted into the body cavity while grasping the proximalportion of the guide wire 14 to maintain it at its location adjacent thetarget area. Thus, the entire operation may be performed by oneunassisted operator.

The catheter 10 may also include a stiffening member 36 that extendsdistally from proximal end 24 of the catheter 10 along a portion of thelength thereof. The stiffening member 36 increases the longitudinalstrength and rigidity of the catheter 10 to facilitate insertion of thedevice into body lumens. In particular, the stiffening member 36stiffens the proximal portion of catheter 10 where guide wire 14 isexternal to catheter 10 (i.e., the portion of the catheter 10 proximalof the proximal port 20). Thus, the stiffness of the catheter 10 ismaintained along its length despite the fact that a guide wire 14 is notpresent through the proximal portion thereof. In one exemplaryembodiment according to the present invention, the stiffening member 36extends from the proximal end 24 to a location proximate to the balloonportion 16. However, those skilled in the art will understand that thestiffening member 36 may extend distally beyond the past the proximalport 20 to enhance the stiffness of the distal part of the catheter 10.In one specific exemplary embodiment, the stiffening member 36 fitswithin a second lumen of the catheter 10, such as stiffening memberlumen 38, which may extend from the proximal end 24 to a proximal end ofthe balloon portion 16. More preferably, the stiffening member 36 willextend from the proximal end 24 to the proximal port 20 so that thestiffness of the catheter 10 with a guide wire 14 received therein issubstantially constant along its length. The guide wire 14 imparts tothe portion of the catheter 10 extending distally of the proximal port20 an additional stiffness substantially equal to that imparted to theproximal portion of the catheter by the stiffening member 36 so that thecolumn strength of the entire catheter 10 is sufficient to enable it tobe pushed through the body lumen to the target area.

The stiffening member 36 may be adapted to fit into any of the lumens ofthe catheter 10 to facilitate manipulation of catheter 10 by theoperator. For example, a handle portion may be provided at the proximalend of the stiffening member 36 to facilitate grasping the device. Therigidity of the stiffening member 36 is preferably selected such that,once it is has been inserted into the lumen 38, the catheter 10 remainssufficiently flexible to follow the curvature of the duct or cavitybeing treated, but at the same time has column stiffness required toallow it to be pushed through the body lumen to the target area. Thestiffening member 36 may optionally be removable from the catheter 10.In one embodiment, as shown in FIG. 1, a lock 40 may be used to securethe stiffening member 36 in place relative to the proximal end 24. Aswould be understood, when in an open configuration, the lock 40 permitsremoval of the stiffening member 36 from the lumen 38 while, when in theclosed position, the lock 40 prevents removal of the stiffening member36 therefrom.

The catheter 10 may be provided with additional lumens used to carry outvarious functions. For example, certain procedures may require injectionof a contrast media to the target area to assist in fluoroscopicvisualization of the region being treated. Alternatively, a proceduremay require injection of a therapeutic agent to treat the target area.Thus, the catheter 10 may include an injection lumen with an exit portdistal of the balloon portion 16. The catheter 10 may include separateinjection lumens for contrast media and therapeutic agents or thesefluids may be applied via a single multi use lumen of the catheter 10.In one exemplary embodiment, the lumen 38 may be used to carry thevarious agents, as well as to hold stiffening member 36. In that case,the lumen 38 will extend all the way to the distal end 22 of catheter10, while only a proximal portion thereof is occupied by the stiffeningmember 36. In other embodiments, the stiffening member 36 may utilize aseparate lumen of the catheter 10, or may be secured to the catheter 10without the use of a lumen, for example by being integrated into orattached to a surface of a lumen the catheter 10.

The catheter 10 according to the present invention includes an opening(i. e. port 20) near balloon portion 16 through which the guide wire 14may enter and/or exit the guide wire lumen 42. Care must be taken toprevent fluids from entering the catheter 10 and/or leaking from thecatheter 10 at this location. A sheath 50 may be placed over the distalportion of catheter 10 to prevent leaks during injection of fluidsthrough the various lumens of the catheter 10. In one embodiment, thesheath 50 may extend distally from a point proximal of the proximal port20 a predetermined distance past the proximal port 20. The sheath 50may, for example, be between 0–30 cm in length. In this manner theproximal port 20 is sealed by the sheath 50, and any leaks that may format the exit of the guide wire 14 are contained therewithin. At the sametime, bodily fluids and contaminants are prevented from entering thecatheter 10. For example, the sheath 50 may be made of a polymericmaterial that is heat-shrunk over catheter 10.

A catheter 10 according to the present invention may, for example, beused to dilate a pulmonary bronchial tube. The procedure may begin byinserting a bronchoscope near the target region and extending a guidewire 14 distally therefrom. Alternatively, the guide wire 14 may beinserted separately from the bronchoscope. The bronchoscope is then usedonly for visual guidance of items to the point within the body lumenswhere the diameter is reduced to a level insufficient to accommodate thebronchoscope. The guide wire 14 is then extended from the bronchoscopeand moved into the selected bronchial tube until its distal end 26reaches the target area, as ascertained using, for example, fluoroscopy.From this point on, the distal end 26 of the guide wire 14 should not bedisturbed from its position near the target area to be treated.

The proximal end of the guide wire 14 is then inserted into the distalport 18 of the guide wire lumen 42 and the catheter 10 is slid along theguide wire 14 until the guide wire 14 exits from the proximal port 20.During the insertion of the guide wire 14 into the catheter 10, asdescribed above, the operator grasps the portion of the guide wireextending distally from the catheter 10 to maintain the position of theguide wire 14 relative to the target area. Once the guide wire 14 hasexited from the proximal port 20, the operator grasps this proximal partof the guide wire 14 and slides the catheter 10 along the guide wireinto the body lumen until a distal end 22 thereof reaches the targetarea. This procedure may be carried out by one operator unassisted,since it is easy to maintain control of the shorter guide wire with onehand, leaving the other hand free.

Once catheter 10 is in place, an inflation fluid may be introduced toexpand the balloon portion 16. The bronchial tube is thus dilated, andtherapeutic agents may be introduced through catheter 10 to furthertreat the bronchial tube. If catheter 14 is to be replaced by a secondcatheter, the operator may simply hold in place the exposed portion ofguide wire 14 with one hand, and pull out the catheter 10 with the otherhand until the distal port 18 exits the body. At this point, theoperator grasps the portion of the guide wire 14 extending distally fromthe distal port 18 and completely removes the catheter 10 from the guidewire 14. Thereafter, any desired catheter may be coupled to the guidewire 14 and advanced to the target area. Exchanging the catheter may berequired, for example, in the case of failure of the first balloon todeploy, or if closer inspection of the target site reveals the need fora different surgical tool to treat the cavity, etc.

In the preceding specification, the present invention has been describedwith reference to specific exemplary embodiments thereof. It will,however, be evident that various modifications and changes may be madethereto without departing from the broadest spirit and scope of thepresent invention as set forth in the claims that follow. Thespecification and drawings are accordingly to be regarded in anillustrative rather than restrictive sense.

1. A flexible catheter for insertion into a body lumen, comprising: aguide wire lumen extending from a distal port at a distal end of thecatheter to a proximal port separated from a proximal end of thecatheter; a stiffening member lumen separate from the guide wire lumen,the stiffening member lumen extending from the proximal end of thecatheter to an opening at the distal end of the catheter so that fluidsupplied thereto is delivered to an area of the body lumen adjacent tothe distal end of the catheter; and a stiffening member extending withinthe stiffening member lumen from the proximal end of the catheter to apoint adjacent to the proximal port.
 2. The flexible catheter accordingto claim 1, further comprising an expandable element mounted adjacent tothe distal end of the catheter for dilating a lumen in which thecatheter is inserted.
 3. The flexible catheter according to claim 2,wherein the expandable element includes an inflatable structure coupledto an inflation fluid lumen.
 4. The flexible catheter according to claim1, wherein the expandable element is mounted between the proximal anddistal ports of the guide wire lumen.
 5. The flexible catheter accordingto claim 1, further comprising a stiffening member locking mechanism tolock the stiffening member within the stiffening member lumen.
 6. Theflexible catheter according to claim 1, wherein the proximal port is alateral port formed on a side surface of the flexible catheter.
 7. Theflexible catheter according to claim 1, further comprising a sheathencasing a portion of the flexible catheter including the proximal port.8. The flexible catheter according to claim 7, wherein the sheath isformed of an impermeable material.
 9. The flexible catheter according toclaim 1, wherein the inflatable structure includes a balloon whichexpands radially from the flexible catheter when inflated.
 10. A methodof treating tissue at a target location within a body lumen, comprisingthe steps of: inserting a guide wire through the body lumen to thetarget location; inserting a proximal end of the guide wire into adistal port of a guide wire lumen of a catheter and sliding the cathetertherealong until the guide wire exits a proximal port thereof, theproximal port of the guide wire lumen being spaced from a proximal endof the catheter; sliding the catheter along the guide wire to the targetlocation; inserting a stiffening member into a stiffening member lumenuntil the stiffening member extends between a proximal end of thecatheter and a point substantially equally distal thereof with theproximal port, the stiffening member lumen separate from the guide wirelumen and extending from the proximal end of the catheter to an openingformed in a distal end thereof; and treating tissue at the targetlocation using the catheter.
 11. The method according to claim 10,further comprising removing the catheter from the body cavity by slidingsaid catheter along the guide wire, and threading a second catheter ontothe guide wire to guide the second catheter to the target location.